When large thin flat boards are used as the base for forming a monolithic wall, it has been common to form the side edges of the board tapered and slightly thinner than the rest of the board. When two tapered edge boards are affixed side by side, a wide, shallow V-shaped groove is formed which can be filled with a joint concealing material to hide the joint, with the joint concealing material being troweled smooth and flush with the rest of the board.
Substantially all homes and a large percentage of commercial construction involves the use of gypsum wallboard with tapered side edges, concealed by paper tape and joint compound. Prior patents have suggested methods for forming tapered end edges on the boards, also, but none have met with any substantial commercial success. One reason for the lack of greater success is that the need arises, too often, for cutting part of the end off, to obtain a desired length, other than the factory length, which cutoff removes one of the two tapered end edges.